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(M/EH070) Are modern pesticides degraded in manure? Sundin, Peter1, Ramberg, Åsa1, Volkova, Laima1, Kylin, Henrik1, Torstensson, Lennart2, 1 2 ABSTRACT- Farm practices may involve the disposal of pesticide-containing wastewater by addition to manure. In fact, such practises have been recommended by swedish authorities. The fate of pesticides in manure, however, has not yet been thoroughly studied. If degradation does not take place the result may be that pesticide-amended manure is distributed to the crop. This may result in that the crops wither away or do not grow properly. In Sweden, cases have been reported where oil-seed crops have shown damages characteristic to the effects of sulfonyl urea herbicides, after distribution of manure from containers that have recieved water used to rinse spraying equipment. In this study 6 pesticides were added to pig and cow manure, and their degradation was followed over a period of 4-5 months. The pesticides chosen were the insecticide esfenvalerat, the herbicides diflufenikan, isoproturon and terbutylazin (added at 50 mg/kg each), and the sulfonylurea herbicides chlorsulfuron and metsulfuron methyl (added at 5 mg/kg each). The mixtures were incubated in triplicate in covered vessels at room temperature. After 17 weeks 30-90% of esfenvalerate, diflufenikan and isoproturon remained, while only about 7% of terbutylazin could be recovered both from pig and cow manure. After 22 weeks about 65% of chlorsulfuron added to pig manure remained, while only about 25% of metsulfuron methyl added to cow manure could be recovered. In conclusion, our results do not support the idea that pesticides in general will be degraded when added to manure. On the contrary, certain pesticides added to manure, sulfonyl urea herbicides in particular, may cause crop damage when the manure is used for crop fertilization. Key words: esfenvalerate, herbicides, sulfonylureas, incubation |
